Hi!

I do have 2 ISPs. One main ISP which is a leased line and the other is a DSL for backup just in case the leased line went down. I do have one mail server which is connected to the leased line. I just want to ask if it is possible to have multiple IP address on a MX record. In such a way that when the 1st ISP went down, I can then connect the second ISP to the mail server so that it is still broadcasted in the internet. But I am also thinking that it might confuse the DNS because if you will ping the mail.company.com, it might not know which one is up. Thanks.

you seem to have a few principles mixed up there, but essnetially you would just set mx priorities. set your main one as say "MX 10 mail.company.com" and the other as "MX 20 mail_backup.company.com" and off you go.

Hi! I have tried that one before. When logging in on the webmail, I don't get any problem. But when someone uses a mail client like MS Outlook or Thunderbird, it runs really slow. I'm just wondering why and I figured out that these mail clients get locked on the first entry on the DNS that they wouldn't try the second entry. Correct me if I'm wrong in here. Someone even suggested that I should put up two mail servers running both SMTP and POP3 server. Now, I really don't know how two mail servers will be able to syncronize. I mean two servers with two different IPs and having the same data as the other.

imap has nothing to do with MX records. a mail client just hits DNS records for an A record and goes to that address. you would need to configure this totally seperately. if you believe you can synchronize two servers effectively then you could jsut run a round robin dns if you really wanted to be OTT.

acid_kewpie,

My friend.. Just want to revive this thread. What do you mean by OTT? So, do you mean I should just add up two IN A records which is the other mail server and everytime the mail1.company.com gets down, I will need to reconfigure the other email client to retrieve mails from mail2.company.com? Do I get this right?

You may be interested in something like this:

http://www.dnsmadeeasy.com/s0306/prod/mailbk.html

I'm not using it for MX records, but my company is getting ready to move some A record hosting to this service in conjunction with a new High Availability FortiGate firewall and two ISPs for one of our clients. The above link describes their secondary MX service.

Can't this be done using an open source technology of some sort? I mean can you setup a secondary mail server which is on MX 20 priority and just in case MX 10 is down, it will then receive all of your mails and send it back as soon as your server is up. What do you think?

yes, absolutely. just do exactly that and you'll be fine.

Acid_kewpie,

If I setup a secondary email system, shouldn't have all my users synced with the primary mail? Because if for example user1@mydomain.com exists in the primary mail, the secondary mail should also have user1@mydomain.com. Because if the primary mail gets down, it will automatically go the mx 20 which is my secondary mail and if that user doesn't exist on that machine, it will just bounce back to the sender. Do you know any free open source software which can handles that? I now have around 300 email accounts and i think its an hassle to duplicate that one on the secondary mail server. And even if I do create account on the second mail server, I still don't know how I can transfer the mails to the primary domain when it goes up again.